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Effect of high salt diet and antioxidants on vascular function of mesenteric arteries
Author(s) -
Raffai Gábor,
Lombard Julian H
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1153.3
Subject(s) - mesenteric arteries , oxidative stress , chemistry , vasodilation , antioxidant , endothelial dysfunction , medicine , endocrinology , catalase , nitric oxide , acetylcholine , pharmacology , biochemistry , artery
This study compared vascular function in mesenteric arteries of male Sprague‐Dawley rats fed high salt (HS, 4% NaCl) or low salt (LS, 0.4% NaCl) diet. External diameter of perfused and superfused vessels was recorded at 75 mmHg. Norepinephrine (NE) sensitivity and acetylcholine dilation (of NE precontracted vessels) were determined. The effect of acute antioxidant application (bath) and chronic (drinking water) tempol treatment on vascular relaxation was tested. EC50 of LS (4.1±0.95μM) and HS (3.2×0.85μM) vessels to NE was not different. Vasorelaxation was suppressed in HS (6.2±2.8%) compared to LS (16.9±2.6%). Extraluminal (EL) tempol did not improve endothelial function in HS (5.7±2.5%) and reduced vasorelaxation in LS (2.7±4%). In contrast, intraluminal (IL) tempol [similarly to other EL antioxidants (PEG‐SOD, PEG‐SOD+tempol, PEG‐catalase+tempol)] ameliorated impaired relaxation in HS (10.5±2.3%) without affecting LS responses (13.5±2.8%). Chronic tempol treatment did not influence vasorelaxation responses in LS (10.9±4.8%), but prevented the deleterious effect of HS on endothelial function (13.5±3%). These results indicate that HS diet impairs vascular relaxation by increasing endothelial oxidative stress. EL tempol (unlike IL tempol and other EL antioxidants) cannot reduce such an oxidative stress, but might restrict responsiveness to vasodilator stimuli. (NIH #HL‐65289 and #HL‐72920).